Radio signaling system



Dec. 4, 1928.

R. S. OHL.

RADIO SIGNALING SYSTEM Filed June 25, 1924 E B f INVENTOR MZ BY dectw- ATYORNEY V Patented Us@ 4, 1928i i resista 'r trios; i

itiiss'uii. ouiiiiii rouifir'kii.' it., Assreuonro AMEiaioAN TELEPNE Ni) TELEGRAPH ooMrANY, A CoRPoRATIoN or NEW YORK.

, 'Sannio Y si'GNALiNG SYSTEM.

.This inyention relates `to high frequency signaling systems, and particularly tota receiving circuit of. sunclrsystems che acterized by the Auseofalternating Current for-heating the iilamentsrof the vacuum tubes used in the re-A ceiying circuit.` A

jThe usek of batteries, partioularly of the storage type,in connectionWithiyhigh frequency receiving setsA is objectionable, not

onlybecauseof high lirst cost andmaint'enance but alsobeoauseofthetroubleincidental to -keeping suo-hbatteries charged, Itis ac -V cordinglyfdesirable; to; avoidvtheir use. been foungh that Van* alternating; current supply, sucln-asj the (Ofcyole lighting circuits, may be used for tile heating Aofthe filaments Oifeiaacuum .tube ampliers Without producing appreciable noise inithereceiver connected with ythe;outpin;side:thereof, provided :ex-

Whichis eliaracteriiefdby the use ofon'ezor more magnetio detectors andfbygintermediate frequency ,-amplioationg, utilizing .vacuum tubes,` the filaments of which are heated by alternating,currents. i i

Otherobjeets of this invention will `be apparent from the following descriptioni ,when read in connection With the attached drawing, of which. Figure@ showsarfoiin of embodiment ofithe .invention employing ztu'omagnetic detectors and intermediate frequency amplification, andV Fig shows the use of .a if'aeuuin tube. for the;intermediatefrequency `detection and afinagnetic detectorffor the audio-frequency detection. t, j Y i fln FigrL' theanteiina lis connected With la resonant'inputbircuit comprising the vari? able-eondenser 2 and an induotan'ce 8,1 which constitutes one `Winding of tlie'fma'gnet-ic Vdetector Anotherwvinding 5 ofthis detector -isconnected with the oscillator l0. i Athird Winding 6 is connected Withlthevacuum tube am-liilorg-aud a fourth Winding? is .connected'with a source of direct current, namely the niet@ battelzyifl fr@ riil'rosfe Otbis'ielsn'etically the detector Vl-, The cores ofthisdetector are preferably made ofxperinalloyltthe' charateristiosdof which arelifully setgforth in e reperti A111101@ and Elieniuublehed in the Journalfof theFranlglin,Institutefyolume 195, No- 5, dated- Mfu, 1923-; A variabler@- sistance` 8*.isconnected in parallel with the Winding to control the current therein anda condenser Lthis. connected] to" 4groiuid for reasonswhiclruillube clear from A-later description.` variable, jconclenser llns oonnested @GITQSS the Wind-,ine @Provide a resonant-feed-'bekirutof the @Seillatr l0, and af. resistance1.12y is connected toground fromthe grid circuitof this tube. The am; pluiemay Cmeinifanyinumbe: arabes., SuQ11.aSl3-ll=; and, 115., @verleid `.together by means, 0f transformers 17 fand. .l8-A flhe in: ducten@ 1.9 senrlclted WithV the plate @fthe lest tube 1.5;, The yplete Ofttis ftulieis @Orf neotedthrough Loonvdenser.. 2Q with onductor 2.1,` which is Connect-,ed with the ,Winding 22i of the. inagneti detector, o AnotlielW-ndng 24- is connected with a signal indicating deri@ suchas atelephone receiver. 25r A biasing windng, Simulatie? oi detector` his connected with, detector 23v and a- Shuut 29 controls the Y current thuough this winding. Thefilaments oftheampliier and zilSQ Qf the oscillator are connected Withanalternating current generatory 16,;aeross which is Connectedthe resistaneeBO, the `midpoint 4of which is conneote'd `with the, positive pole. of the7 battery 28 the negative l.poleof whicln is ground: ed. vThis battery, appliesthe negative bias to the grids olf, the:amplifier,and,,oscillator Battery 27 serves by means ofconductors l3l and 32 to apply the positive yplate.potential to allofthe tubes and alsoto providezthe biasingurrent for the windings 7 and 26 of the magnetic.;detectors.- l u i, t f

AThe manner in which this arrangement op.- erates to detect :signals is asf follows the cui".n rentsof signaling frequency'received b'y the antenna l ivillbe. impressed by fthe resonant eirouitafff uponr the magnetiovdetector 4, Wherein'such eurrentslwill loebeaten to anin termediate or diiferentfrequenoy by another frequency impressed upon the Winding y5 by the oscillator.v 1Q. f'llherresultani interine- -diate frequency Will be iinpressedupon the amplifiers 13, 14 and 15, andraftei beingainplied to the required. degree, the said lintermediate frequency carrying the signal Will be impressed upon the winding 22 of the del tector 23. The signal will be detected thereby and impressed upon the receiver 25 by the winding 24. i

Fig. 2 shows anembodiment of the invention in which a detector of the vacuum tube type is used for the det-cction of the intermediate frequency. The circuit of Fig. 2 differs structurally from that of Fig. 1 in the use of a vacuum tube detector in place of the magnetic detector shown in Fig. 1 for beating down the inconiing frequency to an intermediate frequency. In the arrangement of Fig. 2 the high freqiu-mcy signaling currents received by antenna 1 will be impressed upon the rc:` nant circuit 2 33 which in turn will impro, then upon the resonant circuit 3ft-35 connected with the grid circuit of the vacuum tube detector 3S. Coupled with this grid circuit by means of the windings 36 and 37 is a source of high vfrequency current similar to that shown in Fig. 1. The intern'iediate frequency current resulting from detection by the tube 38 will be impressed by the transformer 39 upon an amplifier similar to that shown in Fig. 1, but of which tube 13 only is shown in Fig. 2. The remainder of the circuit of Fig. 2 for the detection of the audio-frequency signals should be the same as shown in Fig. 1. The arrangement shown in Fig. Q'is preferable where the incoming frequency is so high that satisfactory detection of the intermediate frequency cannot be effected b-y means of any known type of magnetic detector.

IVhile this invention has been disclosed as embodied in a particular form, it is to be understood that it is capable of embodiment in other forms without departing from the spirit and scope of the appended claims.

What is claimed is:

1.V Ina radio receiving system, the combination with an antenna of a magnetic detector connected therewith, an amplifier connected with the output of the said detector, a second magnetic detector connected with the output of the said amplifier, and a signal receiving instrument connected with the said second detector. i

2. In a radio receiving system, the combination with an antenna of a n'iagnetic dictee tor connected therewith, a vacuum tube aniplilier connected with the output of the said detector, the said ampliiier having a source of altern ating current connected with the lilament thereof for heating the said filament, a second magneticdetector connected with the output of the said amplifier, and a signal receiving instrument connected with the said second detector.

3. In a radio receiving system, the combination with an antenna ofa magnetic detector connected therewith, a vacuum tube amplifier having a plurality of tubes connected with the output of the said detector, a source of alternating current connected with the lilaments of the said vacuum tubes for heating the same, a second magnetic detector Connected with the output of the said amplifier, and a signal receiving instrument connected with the said second detector. i

fi. In a radio receiving system, the combination with a timed receiving circuit of a magnetic detector including a plurality of windings mounted upon a magnetic core, one of said windings constituting one of the elements for timing Vthe said receiving circuit, a vacuum vtube oscillatorconnectedwith another of the said windings, a source of biasing current connected with a third one of said windings, a vacuum tube amplifier connected with al fourth of said windings, a source of altern ating current to supply the heating current for the .filaments of the said oscillator and sain amplifier, a second magnetic detector having a plurality of windings, one being connected with the out-put of the said amplilier, another being connected with the said source of biasing current, and a signal receiving instrument connected with a third Winding of said second detector.

5. In a radio receiving system, the combination with a magnetic detector having a plurality of windings, of an input circuit connected with one of said windings, an oscillator connected with a second winding of said detector, an amplifier having its input side connected with a third winding of the said detector, and a source of current connected with the fourth winding of the said detector to magnetize the core thereof.

6. In a radio receiving system, the com bination with a magnetic detector having a plurality of windings, of an input circuit connected with one of said windings,an oscillator connected with a second winding of said detector, an amplifier having its input side connected with a third winding of the said detector, a source of current connected with the fourth winding of the said detector, and means to limit the magnitude of the Vcurrent through the said fourth winding depending upon the magnetic characteristic of the detector.

7. In a radio receiving system7 the combination with a plurality of magnetic detectors each having a plurality of windings, one detector being designed for the detect-ion of intern'iediate frequencies and the other of audio frequencies, of an input circuit connected with one winding of the intermediateV frequency detector, an'oscillator connected with a second winding of the said intermediatefrequency detector, an amplifier having its input connected with a third winding of said intermediate frequency detector and its output connected with a winding of the audio frequency detector, a receiving device con nected with a second winding of said audio frequency detector, and a source of direct current connected with a fourth winding of the intermediate frequency detector and also witha third winding of theaudio frequency detector to provide a predetermined degree of magnetization of the cores of the said detectors.

8. In a radio receiving system, the combi- Vplate voltage connected with the plates of said vacuum tubes and also with the fourth l, winding of the said detector, and a source of alternating current connected with the filaments of the saidvacuum tubes.

9. In a radio receiving system, the combiintermediate frequency and the other of an audio frequency, of an input circuit connected with one winding of the intermediate frequency detector, a vacuum tube oscillator connected with a second winding of the intermediate frequency detector, a vacuum tube amplifier having its input connected with a third winding of the intermediate frequency detector and its output connected with a winding of the audio frequency detector, a receiving device connected with a second winding of the said audio frequency detector, a source of alternating current connected with the filaments of the said vacuum tubes, and a source of platevoltage connectedwith the plates of the saidvacuum tubes and also with a fourth winding of the intermediate frequency detector 'and a third winding of the audio frequency detector.

In testimony whereof, I have signed my name to this specification this 21st day of June, 1924.

RUSSELL S. OHL. 

